﻿<!DOCTYPE html>
<html>
<head>
    <meta charset="utf-8" />
    <title>if语句的应用</title>
</head>
<body>
    <p>如果时间早于 20:00，会获得问候 "Good day"。</p>
    <button onclick="myFunc()">获得问候</button>
    <p id="demo"></p>
    <script>
        function myFunc() {
            let x = "";
            let time = new Date().getHours();
            if (time < 20) {
                x = "Good day";
            }
            document.getElementById("demo").innerHTML = x;
        }
    </script>
</body>
</html>